Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

Air Pollution a Leading Cause of Cancer, UN Agency Says

The United Nation's World Health Organization (WHO) has classified air pollution as a prime cause of cancer worldwide, especially in the case of lung cancer.

The WHO's International Agency for Research on Cancer (IARC) has now placed dirty air in the same category of carcinogens as tobacco smoke, ultraviolet (UV) radiation and plutonium, BBC News reported.

According to IARC, about 223,000 lung cancer deaths globally can be blamed on exposure to air pollution. The majority of these deaths are occurring in rapidly industrializing Asian nations such as China.

Brothers Eric and Ryan Jensen, the Colorado cantaloupe growers whose farm was linked to a deadly 2011 listeria outbreak, said Tuesday they would plead guilty under a deal with federal prosecutors.

Thirty-three people died in the outbreak, and last month the brothers were charged with introducing adulterated food into interstate commerce, the Associated Press reported.

The U.S. Food and Drug Administration said the charges laid against the Jensens were meant to send a message to food producers everywhere. The brothers each faced up to a 6-year prison term if convicted of the original charges, the AP said.

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Seniors' Prescription Drug Use Varies Widely by Region: Study

Seniors living the American South are more likely than those living elsewhere to receive prescriptions for drugs deemed risky by experts, but less likely to be prescribed certain medications that might help them ward off heart attacks, a new study has found.

Overall, more than 1 in every 4 Medicare patients across the United States received at least one prescription for medications deemed risky for seniors, according to the study from the Dartmouth Atlas Project, the Associated Press reported.

But the problem was more widespread in the South. For example, a senior in Alexandria, La., was more than three times as likely to receive one of these potentially harmful drugs compared to a senior in Rochester, Minn. Examples of these riskier medications include muscle relaxants or anti-anxiety drugs, both of which have been linked to excessive sedation, falls and other problems, the AP said.

There were disparities in who received potentially helpful drugs, as well. For example, seniors who had already had a heart attack were much more likely to get a cholesterol-lowering statin drug if they lived in Utah than if they lived in Texas, the study found.

"There's no good reason" for these regional disparities in prescribing trends, lead researcher Dr. Jeffrey Munson, an assistant professor at the Dartmouth Institute for Health Policy and Clinical Practice, told the AP.

He said physicians "really need to ask themselves, 'Is there a good reason why my patients are getting less effective care than patients in the other regions.' "

Patients must be more vigilant, as well, Munson said, and ask their physician why a particular medicine is being prescribed, its pros and cons, and any available alternative therapies.